21,640 in words
21,640
twenty-one thousand six hundred forty
21,640 is written twenty-one thousand six hundred forty.
Ways to write it
- As an ordinal
- twenty-one thousand six hundred fortieth
- Expanded form
- 20,000 + 1,000 + 600 + 40
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 6 | 600 |
| tens | 4 | 40 |
| ones | 0 | 0 |
Number facts
- Even or odd
- Even
- Prime or composite
- Composite
- Factors
- 1, 2, 4, 5, 8, 10, 20, 40, 541, 1,082, 2,164, 2,705, 4,328, 5,410, 10,820 and 21,640 (16 factors)
- First 10 multiples
- 21,640, 43,280, 64,920, 86,560, 108,200, 129,840, 151,480, 173,120, 194,760, 216,400
- Square
- 21,640 × 21,640 = 468,289,600
- Square root
- ≈ 147.11
- Sum of the digits
- 2 + 1 + 6 + 4 + 0 = 13
- Rounded to the nearest 10
- 21,640
- Rounded to the nearest 100
- 21,600
- Rounded to the nearest 1000
- 22,000
- Number before
- 21,639
- Number after
- 21,641
- In binary
101010010001000
Quick check
What number comes just after 21,640?
Show the answer
21,641
Is 21,640 even or odd?
Show the answer
Even
What is 21,640 + 10?
Show the answer
21,650
Practise with a game
Factors, Multiples & Primes
Multiples, factors, prime numbers, square numbers and prime factors.
Number Patterns
Find the missing number in a sequence.Frequently asked questions
How do you write 21,640 in words?
21,640 is written "twenty-one thousand six hundred forty".
Is 21,640 a prime number?
No. 21,640 is a composite number, because it has more than two factors.
What are the factors of 21,640?
The factors of 21,640 are 1, 2, 4, 5, 8, 10, 20, 40, 541, 1,082, 2,164, 2,705, 4,328, 5,410, 10,820 and 21,640.